Resistance-grid.



N. WILKINSON.

RESISTANCE GRID.

APPLICATION FILED APR.8, 1911.

1,088,003. Patented Feb. 24,1914.

wA/wA/Mpwv 5 UNITED STATES PATENT OFFICE.

NATHAN WILKINSON, OF MILWAUKEE, WISCONSIN, ASSIGNOR, BY MESNE ASSIGN- MENTS, TO ALLIS-CHALMERS MANUFACTURING COMPANY, A CORPORATION OF DELAWARE.

RESISTANCE-GRID.

Specification of Letters iatent.

Patented Feb. 24, 1914.

To all whom it may concern Be it known that I, NATHAN lViLKINsoN,

Milwaukee, in the county of Milwaukee and State of lVist-onsin, have invented certain new and useful Improvements in Resistance-g Grids, of which the following is :1 full, clear, 1

and exact specification.

My invention relates to the construction of resistances for use in electric circuits.

Among the objects of my invention are to obtain strength, durability, compactness, i

and cheapness of-construction.

In addition to providing a resistance possessing superior structural features, the ar- 1 rangement is such that the par-ts may all be readily assembled and firmly held in a permanent or fixed position, except those parts intentionally made/movable.

In this construction, grids are so formed and assembled that one or more of the grids comprising the resistance, can be taken out and replaced in case of breakage orinjury without much trouble.

Conspicuous among the feautres of improvement is a structure of sheet metal the elementsjof'which are made especially stifi' to meet the'requirements of any service for which they are intended and to which they may be subjected.

The various novel features of my invention will be described in the specification and particularly set forth in the appended claims. v

I The invention is illustrated on the accom= panying sheet of drawings, in which Figure 1 is a side elevation of a grid emv bodying my invention; and Fig. 2 is an end elevation of the grid shown in Fig. 1.

Resistance grids have been made very heavy and bulky in structure in order to withstand jars and tendencies to warp out of shape when excessively heated. The resistance grid shown in these drawings is made light in structure. This grid is made of suitable resistance material, preferably of sheet metal punched in zig-zag form, for example,

I substantially as shown in Fig. 1, so as to reduce into comparatively small space a resistance of great length.

The resistance grid consists of a conductor 10 formed substantially as shown and having its elements, such as 11, parallel and connected to form a number of end turns,.

such a512, the conductor terminating in en- 7 larged ends or plates 15 provided with openngS 16. These openings are adapted to re-' a citizen of the United States, residing at ceive the insulated cross rods or bolts of the suspending frame and the number of grids may be varied according to the desired length of the suspending frame. The end turns are shown as rolled or bent around insulated rods 17 to reinforce the grid structure.- i

The grid is made of comparatively thin material which, under ordinary circumstances, would be unable to withstand the E effects of heating and jarring. The elements of the conductor comprising the grid would warp under comparatively little strain and short-circuit sections or portions of the grid were it not for the fact that these elements i were stifi'ened. In order to render stifi' the elements of the conductor comprising the grid, said elements are flexed transversely, giving said elements the strengthened effect of columns or hollow. cylinders. These ele ments are preferably curved with respect to the plane of the grid. The end turns of the conductors are also flexed or corrugated, as shown at 20, the flcxure of the end turns extending at an angle relatively to the elements to provide for the expansion of the grid when the same has become heated. The end portions 15 of the conductor 10 are stiffened by grooving said portions. on one side to form ribs 18 on the other side thereof. By means of this stiffening and reinforcing, it is possible to use grids which are comparatively frailin structure without having their elements warp to suchan extent when excessively heated as to buckle up or come in contact with each other or portions of the adjacent grids.

There may be many modifications in the precise form and arrangement herein shown and described, and I aim to cover all such modifications which do not involve a departure from the spirit and scope of my invention as setforth in theappended claims.

What I claim aS new is:

'1. A resistance grid comprising a single conductor having end turns provided with flexible corrugations and with portions bent over in the same direction and in alinement,

over portions of said end turns.

2. A resistance grid comprising a sin 1e conductor consisting of a plurality of ements, each element being bent over in. crossand reinforcing members located in the bent,

section, and end turns uniting adjacent ele- 2 Inents, said end turns being provided With flexible corrugations adjacent said elements,

and with portions bent over in alinement to receive a reinforcing member.

3. A resistance rid com risin a sin le b conductor consisting of a plurality of elements, each element being curved throughout its full cross-section, end turns uniting I adjacent' elements and provided with portions bent over in the same direction and dis- 1 posed in alinement, and a reinforcing mem 3 for holding said reinforcing member, said l holding means being connected to said s'ecber held in said bent over portions.

4. A resistance grld comprislng a plurality of parallel elements, each of said elebent overi ments being provided With stiengthening ribs, portions uniting adjacent elements at the ends thereof, said portions being provided with flexible corrugations and With partsbent over in the same plane, and a strengthening member held in said bent overparts.

5. A resistance grid comprising a conductf ing element consisting of a plurality of sections, and portions uniting adj-scent sections at the ends thereof, said portions being provided with flexible corrugations and with bent over parts, and a strengthening member held in said bent over parts.

(i. A resistance grid comprising aconducting element consisting of a plurality of sections, each section having an end connection toan adjacent section, a reinforcing member, and means secured to adjacent sections tions through portions provided with flexibie corrugations.

In testimony' whereof I ailix my signature, in the presence of two witnesses.

-NATI-IAN \VILKINSON. VVi tness'es CHAS. L. BYRON, Ron. E. STOLL. 

